I have implemented QPSK but I have to make changes to OQPSK. On the transmit path I am clear, as I have to delay Q channel by 1/2 symbol.

My receiver costas carrier recovery will not be the same. I have not found much info about this. What changes are required?

Gardner timing recovery will be same as qpsk except the Q channel has to be delayed by 1/2 symbol.

After timing recovery does the constellation look like QPSK? ie. the phase ambiguity block will be like the QPSK

  • $\begingroup$ If you delay assumed I in your receiver by 1/2 a symbol prior to doing anything then won't everything be the same as QPSK? $\endgroup$ Apr 19, 2020 at 12:31
  • $\begingroup$ If i do the 1/2 symbol delay after the RRC in the transmit path will it be same as the qpsk. what are the changes required in carrier recovery and phase recovery? $\endgroup$
    – mark
    Apr 20, 2020 at 4:57
  • $\begingroup$ If you undo that delay (by delaying I) then it will be the same as QPSK and there are no other changes needed, right? $\endgroup$ Apr 20, 2020 at 10:36
  • $\begingroup$ u mean on the recieve side i should remove the delay and process it like QPSK?? $\endgroup$
    – mark
    Apr 21, 2020 at 3:49


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